Generally, the generation of pulsed magnetic fields requires nondestructive resistive coils to be manufactured; to do this, materials having both excellent mechanical and electrical properties are required in order to allow the high current that creates the magnetic field to be transported and to allow the coil to withstand the forces of magnetic origin (Lorentz forces) that tend to break the coil. At the present time, the best candidates for coils generating fields higher than 70 teslas (T) are nanocomposite materials consisting of niobium (Nb) nanostructures inserted in a pure copper (Cu) matrix.
Studies have already been carried out in the field of the development of reinforced (macro and nanocomposite) conductors for high-field coils as notably described in the following articles: “Interface instability in the drawing process of copper/tantalum conductors”, L. Thilly, J. Colin, F. Lecouturier, J. P. Peyrade, J. Grilhé, S. Askénazy, Acta Material A, 47-3 (1999), 853; “Recent progress in the development of ultra high strength “continuous” Cu/Nb and Cu/Ta conductors for non-destructive pulsed fields higher than 80 T”, L. Thilly, F. Lecouturier, G. Coffe, S. Askenazy, IEEE Transactions on Applied Superconductivity, 12-1 (2002), 1181; “A review of established and emerging materials for use as high-field magnet conductors”, K. Spencer, F. Lecouturier, L. Thilly, J. D. Embury, Advanced engineering Materials, 6-5 (2004), 290-297; and “Identification of aging mechanisms for non destructive pulsed magnets operating in the 60 T range”, J. Billette, F. Lecouturier, O. Portugall, IEEE Transactions on Applied Superconductivity (2004), Vol. 14, No. 2, 1237-1240.
However, the nanocomposite conductors based on copper matrices and niobium nanotubes currently studied and/or manufactured suffer from the presence of internal defects that cause breaks and prevent long nanostructured composite wires, indispensable for the manufacture of magnets, from being obtained.